85 Fuel Pressure ?
Max G’s
Joined: Nov 2008
Posts: 2,751
Likes: 78
From: Monroe OH
NCM Sinkhole Donor
85 fuel pressure
A publication I have says that GM recommended fuel pressure for 1985 model year is between 34-40psi. If your car is mainly stock and you have an adjustable fuel pressure regulator, try 42psi.
Supporting Vendor
Joined: Mar 2008
Posts: 1,762
Likes: 14
From: Cumming Ga
the 85 has a recommended rail pressure of 36psi. this is why the 85 uses a 24lb fuel injector. in 86 the regulator was changed and the running rail pressure was increased to 43.5psi to increase atomization of the fuel. At the same time the injector size was reduced to 22lb. If you increase fuel pressure to 43 in a 85 you will have close to a 26lb injector. The engine will run fine but your engine will be rich in open loop and be real fat at WOT
Thread Starter
Heel & Toe
Joined: Feb 2008
Posts: 24
Likes: 0
thank you all for the info - I have done some mods to the car;I.E. Headman Headers, true dual exhaust with flow master mufflers, K&N air filter and a Hypertech chip. the car runs great. I will probably leave the fuel setting alone for now. What do you all think on a larger mm throttle body? Recommendations???
Supporting Vendor
Joined: Mar 2008
Posts: 1,762
Likes: 14
From: Cumming Ga
The yellow top ford/bosch is at almost 22lbs at 43.5 which is about equal to the stock 24 at 36psi. I don't think a mild modded 85 will need much more. Read the plugs and see if you are lean after some heavy driving, if the plugs read good, you are ok
Max G’s
Joined: Nov 2008
Posts: 2,751
Likes: 78
From: Monroe OH
NCM Sinkhole Donor
tb upgrade
thank you all for the info - I have done some mods to the car;I.E. Headman Headers, true dual exhaust with flow master mufflers, K&N air filter and a Hypertech chip. the car runs great. I will probably leave the fuel setting alone for now. What do you all think on a larger mm throttle body? Recommendations???
Thread Starter
Heel & Toe
Joined: Feb 2008
Posts: 24
Likes: 0
thank you again everyone this is usefull information. the last thing i am trying to fix is the over-drive on the 4 + 3. it was working fine and recently it stopped going into overdrive. the microswitch on the shifter is good and the oil and filter is also new. any help on this?
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Melting Slicks
Joined: Jun 2005
Posts: 2,938
Likes: 2
From: Arkansas
Here's a bump for you
I wanted to ask a injector question for these other guys
My 82 has a TPI set-up in it. I have a custom chip set for 22# injectors, but I don't remember what year corvette my fuel rail assembly came off of....it was either 85 or 86.
My injectors are stock Corvette injectors, is there a part number on them that will tell me if they are 22 or 24 lbs?
Thanks!!
I wanted to ask a injector question for these other guys
My 82 has a TPI set-up in it. I have a custom chip set for 22# injectors, but I don't remember what year corvette my fuel rail assembly came off of....it was either 85 or 86.
My injectors are stock Corvette injectors, is there a part number on them that will tell me if they are 22 or 24 lbs?
Thanks!!